As a method of detecting a target using images captured from plural image sensors, a method of calculating a distance of each pixel of an image in a real space using a pair of images according to the principle of triangulation so as to detect a three-dimensional object is known in the related art (PTL 1). In this method, groups of pixels whose positions on the images are close to each other and whose calculated distances in a real space are also close to each other are detected, and a group of pixels having a predetermined size or more is detected as a three-dimensional object. As a result, a three-dimensional object can be detected with high accuracy.
In addition, as another method of accurately detecting a target using images captured from plural image sensors, a method of detecting an object moving at a given speed on a pedestrian crossing and identifying the object with high accuracy as a pedestrian is known in the related art (PTL 2). In this method, a pedestrian moving on a pedestrian crossing is detected with high reliability by increasing the detection sensibility thereof such that collision with the pedestrian. is avoided. As a result, a collision accident with a pedestrian on a pedestrian crossing where an accident is likely to occur can be prevented.